03-11-2012, 10:32 AM
Single Slit Diffraction
Single Slit.pdf (Size: 62.54 KB / Downloads: 100)
Aim of the experiment
To plot the intensity distribution of the Fraunhofer diffraction pattern by a slit
and to measure the width of the slit.
Apparatus required
Laser, He-Ne 1.0 mw
220 V AC photocell
Multirange meter with amplifier
Adjustable slit
Screen
Theory
If a beam of monochromatic light of wavelength l falls normally on the
surface of a narrow vertical slit AB of width b, a number of dark and bright
diffraction fringes on the either side of central maximum is observed.
Let q be the angle between fringes on the left or on the right of the central
maximum w.r.t central maximum (angle between the diffracted ray and normal to the
slit).
Results and Calculations
1. Plot Intensity distribution of the diffraction as a function of q parallel to the
plane of the slit.
2. Find the width of given slit from the plot and compare this width with that
measured by microscope .